It would be going on an opaque resin.

Would Tamiya gloss paints work well? Ideally, I'd like something with a reflective, mirror-like finish.

I wonder if you could use a piece of Mylar film, or maybe a piece of metalized window tint?

I would experiment with some of the new color shifting paint from Green Stuff World or Vallejo.

Spray on a white plastic spoon and see if you like the results.

There's also some damn shiny chrome paints developed recently. Check YouTube.

There are some adhesive films with a red or green tint that are made to replicate the coated optics/glass in armored vehicle viewing blocks.  For scale plastic
models

But for visors, most are really a smoke gray, sometimes dark gray almost black or like a charcoal brown.

I can’t say I’ve even seen anyone take a pilot figure with a helmet on but visor up, paint the face, and the apply some clear resin (like for the heavy buildup coatings for tables) with a little tint and build that up for a clear visor.   Maybe something to try.   Would have to make some sort of putty dam so it doesn’t run everywhere.