Preheat oven to 375°F. Lightly spray a 9x13 casserole dish with cooking spray.
Place your chicken breast in an even layer on the bottom of your prepared dish. Evenly sprinkle the salt and pepper on top of your chicken breast. Set aside.
In a medium skillet, saute your onion and garlic on medium heat just until it is translucent and beginning to soften. This will take 2 and 3 minutes.
Once your onions and garlic are cooked, add your cream of chicken soup, cream cheese and dry ranch seasoning mix. Stir them until the cream cheese is melted and all the ingredients are completely incorporated.
Turn off the heat to your skillet and add your sour cream and ½ cup of the shredded cheddar cheese. Stir until smooth and creamy.
Divide your cream cheese mixture evenly and top each chicken breast. Spread out the cream cheese mixture so that your chicken breasts are completely covered. Top your cream cheese-covered chicken with ½ cup of your cooked and chopped bacon pieces.
With your remaining cheddar and Monterey Jack cheese, evenly cover your chicken breast.
Cover your dish with aluminum foil and bake for 20 minutes.
Remove your aluminum foil and sprinkle the cheesy chicken breasts with the remaining ¼ cup of cooked and chopped bacon. Continue to bake for another 20 minutes, uncovered, or until your chicken is cooked through (160°F internal temperature) and your cheese is melted and bubbly.
Allow your baked crack chicken to rest for 5 minutes before serving. Garnish with copped green onions if desired