Welcome to the forums! Getting unsecured revolving credit will be tricky until you have credit reports generated with the three major US credit reporting bureaus: Equifax, Experian, and TransUnion. You mentioned opening checking and/or savings accounts; unfortunately, those accounts in good standing are not reported to those credit bureaus. If you have mixed finances, adding yourself as a joint owner of the checking account should be sufficient.
Being added as an authorized user on any of your husband's cards would be helpful with generating files and scores, although that will take some time (I believe it's 6 months of file activity to generate credit scores) and it's important to note that most financial institutions have their own internal scoring and underwriting that will often wholly discard authorized user accounts. For the American Express Platinum card, two important things to note are that you will not inherit the account history (the opening date will be listed as the day you were added to the account) and there is a $175 additional annual fee for 1 to 3 authorized users. You do receive additional benefits for that fee, however, such as your own Gold status with Marriott and Hilton, your own Priority Pass account and access to their other lounge networks, TSA PreCheck or Global Entry, etc. With the Chase Sapphire, you did not mention whether that was Sapphire Preferred or Sapphire Reserve (there is a legacy Chase Sapphire card but that is uncommon for people to have); if it is the Sapphire Reserve, that would result in an additional $75 annual fee for an authorized user (you do get your own Priority Pass account for that as well, and Chase's version of that is arguably better than Amex's). Chase will report the full account history of his account to your credit reports.
Getting the secured card from NFCU would be a great way to get started in my opinion, or any other secured card products which are known to graduate to unsecured cards and preferably have product change options for better rewards so that you can keep the accounts useful without them merely being stepping stones.
The Amex Global Transfer program is absolutely a great option to pursue as long as your card is still open, or has been closed within the past 3 months. The link for that is here:
https://www.americanexpress.com/global-card-transfers/united-states.html
Welcome @sellingpineapples. 
I like the ideas I'm seeing. Definitely explore AMEX global transfer. That might be the most expeditious way to get your own credit going.
Also, it's great that you're headed to NFCU. You'll probably be able to go with the rep's advice. Head over here if you have questions.
And definitely do the AU thing on a couple of cards. While some banks ignore AUs, you might find yourself in an improved position with others like Discover and Capital One.
First off, 
Pick one or two cards from Amex using the Global Transfer option to report as your own accounts while having hubby add you as an AU on a couple of his accounts (Assuming they're all in good standing.) Wait 9-12 months while the above put your new SSN on the map with the big 3 credit bureaus (Experian, Equifax and Trans Union). By this time you should be able to pick up one or two more cards of your own from Discover, Capital One, NFCU, PenFed CU, FNBO (Evergreen or Getaway), Chase (Freedom/Freedom Unlimited/Amazon and possibly Sapphire Preferred), Elan Financial Services (search this lender for more details.), BoA, Petal and a few others.
NOTE: You're likely going to start seeing credit card offers showing in the mail around now. Please make certain you read the fine print before considering any of them as some will be "rebuilder cards" with exorbitant fees and interest rates. YOU DON'T NEED THESE! Some of the most common ones are Credit One (not the same as Capital One!), Continental Finance, Merrick Bank, Bank of Missouri, Open Sky, Avant, Surge, Reflex, Indigo, Fingerhut, 1st Premier, 1st Applied, Celtic Bank, Mission Lane, Destiny, etc. These are for rebuilding from BAD credit. While you'll quite easily get these types of cards, they're low hanging fruit and you're building from NO credit so no need to waste money getting tied into these fee harvester cards. When in doubt, simply make a post here in the Credit Cards forum and we'll let you know what you're looking at!
You might consider a credit builder loan from a Credit Union (like NFCU or PenFed) to help give you a score bump in the "Credit Mix" category as well. 18-24 months (and with applicable income and perfect payment history), you should be able to land a card, car loan, etc. from most American lenders while getting low to mid tier interest rates.
In 5+ years, with <9% utilization, perfect payment history, credit mix, low inquiries and at least 3 major lenders (Visa/MC/Amex/Discover) reporting, you'll have a solid file and your Fico 8's should be in the 760-800+ range. Your credit is now entering the "sweet spot" where you should be able to get low interest rates and large starting limits (income permitting) from most lenders. Keep up the good work to maintain the credit profile you've worked hard for!
As said around here, building credit is a marathon, not a sprint. Time and perfect payment history are your biggest assets in building a thick, solid credit file. You're more than welcome to come hang with us in "The Garden", which can be found under the "Personal Finance" category while you're growing your file. You don't want to apply for too many cards within a short span as it'll knock your "Average age of accounts" down along with racking up inquiries. As your file ages and thickens, these two things will have a lesser effect on your scores. In the mean time, I'd limit applying for new credit to a maximum of a couple cards at 9-12 month intervals for at least the first 3 - 4 years. Remember, you only need a *minimum* of 3 major bank cards and an installment loan to optimize your scores. Having more does help thicken your file, but from a scoring perspective, not necessary.
Edit to add... Store cards. While these tend to mostly be easy to grab, loading up on a bunch of store cards is not a good idea. If there's a couple that provide useful benefits and/or rewards to you then that's fine. If they happen to be store/retail cards with a Visa/MC/Amex logo, even better. A credit file full of store cards will tend to be frowned on by a lot of the major banks (and strangely can have an effect on insurance rates.) Most of the store cards out there are backed by two different lenders. Synchrony and Comenity, which tend to get weird if you have too many accounts with them, even though they are for different retailers. A search of either in this credit card forum will bring up many accounts of adverse action by both Synch and Comenity, where most of the time it was someone with a lot of accounts backed by one or the other.
@Anonymalous wrote:
@K-in-Boston wrote:<snip>it's important to note that most financial institutions have their own internal scoring and underwriting that will often wholly discard authorized user accounts. For the American Express Platinum card, two important things to note are that you will not inherit the account history </snip>
A FICO score does require 6 months of credit history, but an AU card's history counts. I became scorable after 5 months (not 6) when I was added as an AU to an old card. You're correct that AUs can give a major bump to your score, but they're not a pancea. A lot of lenders discount or ignore AUs. Someone with scores approaching 800 but less than a year of personal credit history is still someone with less than a year of credit history, to most lenders.
Anonymalous, my mentioning of the AU card's history not counting was specific to the American Express Platinum Card. Since about 2015, American Express reports the date that an authorized user was added to any Amex account as the account's opening date and, unlike other lenders, any history on the account prior to this date is not furnished to the credit reporting bureaus. They are the sole lender that I am aware of that does this and this change happened at the same time they stopped backdating new accounts for primary cardholders (i.e. Member Since 1980 opened a new Amex account in August of 2010, Amex reported the opening date to the bureaus as August 1980).