WILL A 1970 NOSE FIT ON A 1979 FIREBIRD?  

To the best of my knowlege none of the 70 parts will fit a 79 at all.  

WHAT ABOUT A 77 OR 78?  

That should work.  

A few years back HPP ran an article on a guy with a 78 Ta that he put an early second gen nose on (70-73), he had to use the rad support, nose and lower valance and possible the hood. He was able to use the original 78 fenders by welding on the tabs for the early lower valance. Also he switched to a 79-81 style rear with the full width tail light panel, which required a 79-81 gastank and filler neck. It can be done, but the 77-78 is probably a simple bolt-on and the hood is definitely the same.