In a food processor combine Chipotles in adobo sauce, chopped red onion, garlic, cumin, salt, pepper, oregano, and juice of two limes.
Process to make a marinade paste for the chicken.
Clean chicken breasts and cut them into smaller pieces (cutting is optional) cutting into two or three pieces per breast allows for better marinade coverage.
In a gallon ziplock bag or bowl with cover combine marinade and chicken breast and allow to sit refrigerated for a minimum of 4 hours and preferably overnight. I have allowed this to sit for 24 hours with perfect results.
Grill or Cook in cast iron skillet until internal temperature reaches 165 degrees. Remove from heat and rest for 10 minutes.
Dice or chop chicken up to bite side pieces for use in tacos, burritos, and my Famous Keto Burrito Bowls!