Mix lime juice, olive oil, garlic, cumin, chili powder, salt, and pepper in small bowl or measuring cup.
2. Step
Place the chicken breasts in a large, gallon-sized freezer bag and pour the marinade over them.
3. Step
Add red onion and bell peppers to freezer bag. Seal freezer bag and ensure excess air is squeezed out. Gently mix contents together so that the marinade fully coats the chicken.
4. Step
Place in freezer and store up to 3 months.
5. Step
When ready to enjoy, thaw completely and pour contents into slow cooker.
6. Step
Cook on low for 6 hours, or high for 3 hours, or until chicken is fully cooked.