Can triamcinolone or nystatin be used for bed bugs bites?

Yes & no: Triamcinolone is a steroid cream that helps to reduce itching. So doc might prescribe that to deal w/bed bugs but it won't treat infection or bites. Nor will Nystatin which is an antifungal used to treat fungus or yeast infections. Check out https://goo.gl/biAA62. May need antibiotics if bites get infected but usually bites are self-limiting. More important to clean bedding etc to prevent more.

Find or move: Are you sure it is bedbugs? Have you seen bedbugs? Do others also have bites? Find the bedbugs and execute them. Or move (don't take them with you). They often nest in a crack in the wall or somewhere else close to a place where people sleep. Triamcinolone will reduce the itch. Nystatin is for yeast, not fungus, and never for bug bites. You probably need professional help.