I am in Fort Worth and one of the nuts welded to the frame truck body to attach one of the four screws to bolt my passenger seat down broke free. I'm looking for someone who can fix this by either rewelding the nut to the frame or fabricating something to secure the seat.

The dealership wouldn't touch it. I've found some autoshops who are backed up a couple weeks. Has anyone had something similar happen and if so who did the repair? I can't see the nut from the undercarriage of the truck, but that doesn't mean it's not possible.

Go try a muffler shop. I had a couple plates welded on a trailer axle at an independent muffler shop in Dallas a few years back.

Find a race shop or 4x4 shop

They can usually make sure its done correctly

Well... at least you know one dealership not to do biz with in the future!

OP are you sure it's on the frame and not the floor pan?

Those kinds of guys can weld damn near anything.