Cook your base. Prepare quinoa or brown rice according to package directions.
Fluff and set aside.
Mix the light ranch. In a small bowl, whisk Greek yogurt, light mayo, lemon juice, ranch seasoning, a pinch of salt, and a splash of water until pourable. Chill while you cook.
Season the chicken. Pat chicken dry. Toss with 1 tablespoon oil, ranch seasoning, and a pinch of salt and pepper.
Sear the chicken. Heat the remaining oil in a large skillet over medium-high.
Cook chicken 4–6 minutes per side, until browned and the internal temp hits 165°F (74°C). Rest 5 minutes, then slice or cube.
Prep veggies. Halve tomatoes, dice cucumber and bell pepper, and slice avocado. If using frozen corn, warm it in the hot skillet for a quick char.
Warm the beans. Heat beans briefly in the skillet with a pinch of salt, or keep them cold if you prefer.
Assemble bowls. Divide greens, grains, and beans among 4 bowls.
Top with chicken, veggies, avocado, and cheese if using.
Finish and serve. Drizzle with the light ranch, scatter fresh herbs, add lime juice, and a pinch of red pepper flakes if you like heat.