I salvaged 1000 feet of board from a poorly installed floor. I’d like to reuse it in lower traffic areas but the tongues are all damaged, most fit together and hold but when a new nail goes in the whole thing splits. Any advice? Should I drive finish nails through the top and putty to cover?

Repair the tongues with carpenter's wood glue. How much work do you want to do.....cut the tongues off, route grooves, install splines/slip tongues into the new groove, reinstall.

I need to move relatively fast. I can’t afford to be out of my house long enough to rebuild each board. Wondering if the wood glue would be sufficient

Wood glue is stronger than the wood itself. When tested, the wood itself will break before the glue joint. So regluing the tongues should make them solid enough to hold the fasteners. Glue should be allowed to dry for 24 hours for maximum strength.......check glue container directions for dry time.