Harbor Freight has a Threaded Insert Riveter Kit for about $23, it includes ten each of insert nuts 6-32, 8-32, 10-24, and 1/4-20 and the installation tool. Most Tinnerman (clip on) nuts are made to slide onto a sheet metal edge where the hole is within 5/8" from the edge. Snap-in nuts require a square hole. Heli-coils usually require drilling out the hole and threading it to the next larger size, then they screw in and reduce the hole to the original thread size. McMaster Carr online has all these items, if you want to compare the different types. The largest hardware supplier company in the world, and anyone can buy there. Same price for everyone no matter how big your company is. Catalogs printed in 11 languages but they only give those to really big buyers.
I buy from McMaster only when I can't find it elsewhere.
They have a huge selection, but they eat you alive on shipping.
The worst part is, they won't tell you the shipping charge until after you've placed the order. 🤬