In, a large sauce or sauté pan, combine chicken, onion, bell peppers, mushrooms and garlic. Cook until onion and peppers are limp and translucent.
Cut Velvetta into cubes and start to add, at this point you may not want to use the whole pound of Velvetta but it depends on how cheesy you like it.
Do not drain any juice; this will help to thin out Velvetta into a sauce. Experiment with garlic, cooking is not an exact science.