Find a new shop. Stephen Pearson probably deals mainly with Jeeps, and always has issues with Nissans and Toyotas because he doesn’t know what he’s doing. Absolutely no practical difference between those trucks and any other trucks. No joke, shop elsewhere, or risk this guy screwing something up to prove his point.
Only things you need to give thought to are backspacing, center bore, and lug nut style. Most steelies take acorn lug nuts and have large center bores to allow them to fit all vehicle makes. That means you’ll likely need hub-centric rings. You can buy them on Amazon or eBay or wherever; they’re a couple bucks for a set of 4. You’ll likely need 100mm-106mm or 100mm-108mm. For the steelies I ran on my 98 Frontier long ago, the center caps somewhat served a centering purpose because they installed between the wheel and hub. I never had balancing issues. Keep in mind that you may have some issues installing both hub-centric rings and center caps like this since they’ll occupy the same space. Also, don’t rely solely on the lug nuts to center the wheel.
Your OE nuts are acorn style, but you might not be able to re-use them unless they're tall enough. Aluminum wheels have thicker mounting surfaces than steel, so short lugs may bottom out on the wheel stud. If your OE lug nuts reach, or almost reach (~1/8”) the wheel hub when the wheel isn’t installed, you’re probably okay. If you do need new ones, they’re M12x1.25.
Not too relevant here, but only notable with Toyotas are when dealing with their mag-style nuts. The basic solution is to just change them to acorns. In my case, I run 17x8 4Runner alloys on my Frontier now...I use 100mm-106mm hub rings and mag-style lugs on it. Works fine.