Lightly pat dry the chicken breasts with paper towels.
In a small mixing bowl, combine cumin, oregano, salt, pepper and chili powder. Rub the spice mixture all over the chicken breasts.
Press the SAUTE button on the Instant Pot and add in 1 tablespoon olive oil. Add the chicken breasts to the heated olive oil and brown on both sides. You will have to do this in batches; do not try to sear all chicken breasts at once. Remove chicken and set aside.
Add the diced onion to the Instant Pot; if needed, add the rest of the olive oil. Cook the onions for 2 minutes. Stir in the garlic and cook for 20 seconds.
Deglaze the bottom of the Pot with chicken broth while stirring. Add in the orange juice and lime juice ; bring to a simmer.
Return chicken to the Instant Pot. Cover and set to PRESSURE COOK on HIGH for 10 minutes. 12 minutes for chicken thighs. Do a Natural Release.
Remove cover from the Instant Pot and transfer chicken breasts to a cutting board. Shred the chicken.