Wash, peel, and dice the 4 cups potatoes into small cubes. Chop the 2 cups chicken, 1 ½ cups diced bell peppers, 1 ½ cups onions, and 1 cup mushrooms. Roughly chop the 2 cups spinach.
Heat 3 tablespoons butteror oil in a large skillet over medium heat. Add the potatoes and cook, stirring occasionally, until golden and crispy, about 10–15 minutes.
Add onions, bell peppers, and mushrooms to the skillet. Cook until softened and lightly caramelized, 5–7 minutes. Season with Salt and pepper and ½ teaspoon garlic powder.
Push the vegetables and potatoes to the side. Add chicken and cook until no longer pink. Mix everything together for even distribution.
Fold in the spinach and cook until just wilted, about 1–2 minutes. Taste and adjust seasonings.
Sprinkle1 cup cheddar cheese over the top and cover for 1–2 minutes until melted.
Divide hash evenly onto plates. Optional toppings: eggs, avocado, or hot sauce. Enjoy your First Watch-style breakfast at home!