Prepare the chicken: In a small bowl, whisk oil, mustard, honey, vinegar, and seasonings until smooth. Place diced chicken in a large bowl and pour mixture over top. Refrigerate chicken 30 minutes to let the flavors meld.
Remove chicken from refrigerator and heat a nonstick skillet over medium-high heat. Dump chicken mixture into skillet and saute 7-10 minutes until chicken is browned and cooked through. Remove from heat and keep warm.
Prepare the quinoa: In a medium pot over medium-high heat, bring broth to a boil then stir in quinoa. Reduce heat to low, cover and let quinoa simmer until cooked and fluffy, about 10 minutes. Remove from heat and keep warm.
Prepare the salsa: In a small bowl, combine all salsa ingredients until combined.
Prepare the quinoa bowls: Divide warm chicken, quinoa, and salsa between 4 servings bowls and top bowls with sliced avocado if desired. Serve immediately.