Preheat oven to 375°F (190°C) and line a baking sheet with parchment paper.
Pat chicken breasts dry with paper towels. Drizzle with olive oil and rub all over both sides.
Season chicken generously with garlic powder, paprika, salt, and pepper, coating evenly on both sides.
Place seasoned chicken on prepared baking sheet and bake for 25-30 minutes until internal temperature reaches 165°F.
While chicken bakes, place cubed potatoes in large pot and cover with cold salted water. Bring to a boil over high heat.
Reduce heat to medium and simmer potatoes for 15-20 minutes until fork-tender.
Drain potatoes thoroughly in a colander and return to pot. Let sit 1 minute to release excess steam.
Add milk and butter to potatoes. Mash with potato masher until smooth and creamy. Season with salt and pepper to taste.
Once chicken is cooked, let rest on cutting board for 5 minutes to allow juices to redistribute.
Slice chicken into bite-sized pieces or strips.
Divide mashed potatoes evenly among 4 serving bowls. Top each with sliced chicken, corn, shredded cheddar cheese, crumbled bacon, and sliced green onions.
For extra melty cheese, microwave each bowl for 30 seconds or broil for 1-2 minutes until cheese bubbles.
Notes
Chicken thighs work great too and add extra juiciness. Adjust baking time to 30-35 minutes and check internal temperature reaches 165°F.
Make components ahead: cook chicken and prepare mashed potatoes up to 2 days in advance. Store separately and assemble when ready to serve.
Customize toppings with sour cream, diced tomatoes, black beans, jalapeños, or different cheese varieties.