Sure thing, we can offer you lots of unbiased advice.
But first, we need to know a little bit more about your situation. What is your total current monthly spending, and what are your future financial goals? How long do you want your money to last?
I ask because you report you're currently bringing in $4600/mo and have another ~600/mo guaranteed to you by your Nationwide investment's RMDs. If you're spending less than about $5k/month and don't have any other major expenses on the horizon, then you're probably all set.
I advocate for low-stress solutions, for people in retirement. You might be able to make a little more than 3.5% by moving your money out of Nationwide (and avoiding their fee structure), but then again you could also lose a bunch of it if you choose a riskier investment. In your shoes, I'd focus on keeping my expenses under control and riding that smooth gravy train all the way to the last stop.
Some of those "guaranteed 3.5%" investments are actually annuity products with high annual fees, hidden surrender charges, and zero redemption value at death. You should probably read the fine print on your plan to find out what you actually own.