Chop the onions, pepper and mushrooms into slices.

Dice the chicken breast

In a pan fry the onions, red pepper, mushrooms and chicken breast until the chicken is nearly cooked though.

Add the fajitas seasoning and stir until the chicken is covered and cooked.

Place some tortilla chips in a bowl.

Cover with grated cheese and grill for a couple of minutes until the cheese melts.

Add the chicken mixture to the top of the nachos

Serve with salsa and sour cream if desired.