Heat the pan. Heat the oil. Put the meat in. It's basically starting to brown immediately.
Like the blind kitchen says- use your ears and nose. It should sizzle immediately when you put the meat in (just a gentle sizzle, NOT a violent sizzle). And it should start smelling good pretty quickly.
Defrost first. Don't try to brown too much at once (the meat needs to touch the oil and the pan).
EDIT: Oh, I think you're trying to make chili "all at once" by skipping the browning. Yes, it's safe. No, it won't taste as good. Browning is about flavor, not safety. When you cook a steak, you sear it for the crust, then continue cooking to get it up to temp. If you cook a steak in a low-temp sous vide bath, you do the reverse. You get the meat up to temp in the bath. Then when you're ready to eat, you finish it by searing it in a pan.
For anyone making tacos at home: If you don't get to the point where you hear the sizzle, you're making tacos out of steamed meat, not browned meat. This is an easy fix that will seriously up your taco game (unless for some reason you like grey tacos).