Heat 1 tbsp. oil in large, deep skillet over medium-high heat. Using paper towels, pat chicken dry; season all over with Adobo. Add chicken pieces to skillet skin-side down. Cook, flipping once, until golden brown on both sides, about 10 minutes. Transfer chicken to plate.
Pour remaining oil into skillet. Stir in onions and bell peppers. Cook, stirring occasionally, until vegetables are soft, about 7 minutes. Sprinkle Sazón over vegetables; cook until fragrant, about 30 seconds more. Pour coconut milk into skillet with vegetables. Transfer chicken to skillet skin-side up, arranging in single layer; bring coconut milk to boil. Reduce heat to medium-low. Simmer, covered, basting chicken occasionally with sauce, until chicken is cooked through (internal temperature will register 165˚F on quick read thermometer when inserted into thickest part of thigh without touching the bone), about 25 minutes
Transfer chicken to platter; loosely cover with foil. Increase heat to medium-high. Simmer coconut milk sauce, stirring occasionally, until sauce thickens slightly. Stir in cilantro; season with Adobo, if desired
To serve, pour sauce over chicken. Serve with rice and tortillas.