Preheat oven to 350°F.

Season chicken breasts with Italian seasoning and garlic powder.

Grill chicken until fully cooked, reaching an internal temperature of 165°F.

In a skillet, cook bacon until crispy.

Spread a thin layer of butter over each cut side of the French bread.

Lay sliced provolone cheese over the bread, followed by the shredded cheddar.

Chop the grilled chicken into bite-sized pieces.

Crumble the cooked bacon.

Spread the chopped chicken and crumbled bacon evenly over the cheese.

In a small bowl, mix mayonnaise, milk, and ranch seasoning packet to make dressing.

Drizzle ranch dressing over the top of the subs.

Bake in the oven for 15–20 minutes, or until the cheese is melted and bubbly.

Slice and serve warm.