Season the chicken generously with the taco seasoning. Heat the avocado oil in a large skillet over medium-high heat. Add the chicken and cook for 5-7 minutes per side, or until fully cooked. Transfer to a cutting board, let it rest for a few minutes, then slice into bite-sized pieces.
In the same skillet, add the sliced onion and bell peppers. Sauté for 7-10 minutes, stirring occasionally, until tender but still slightly crisp.
Meanwhile, cook the rice according to the package directions.
To make the chipotle yogurt sauce, add the Greek yogurt, chipotle pepper in adobo, adobo sauce, lime juice, cilantro, and garlic to a blender. Blend until smooth and creamy.
To make the guacamole, mash the avocados in a bowl, then stir in the lime juice, diced red onion, salt, pepper, and garlic powder until well combined.
Assemble the bowls by adding the cooked rice, sliced chicken, shredded lettuce, sautéed peppers and onions, and guacamole. Drizzle generously with the chipotle yogurt sauce and serve immediately.