Preheat the oven to 350 degrees F.
Line and 8x8-inch casserole dish with tinfoil. Spray well with a non-stick spray.
Arrange the crackers in a single layer on the bottom of the dish. Break any crackers to fit, if needed.
In a sauce pan over medium-low heat add the butter and stir until melted. Stir in the brown sugar. Increase the heat and bring the mixture to a boil, stirring constantly for about 3 minutes.
Pour half of the brown sugar butter mixture over the crackers and spread with a greased spatula. Top with another even layer of crackers. Pour the remaining sauce evenly over the top and spread.
Sprinkle the top with the Ritz crackers. Place in oven and bake for 7 minutes. Remove from the oven and turn the oven off.
Top the dish with the chocolate chips and peanut butter chips. Place back in the oven (which is turned off) and let set for 8 minutes.
Remove from the oven. With a spatula, smooth the softened chips around to slightly spread out.
Sprinkle with the nuts and pat down gently. Let cool completely. Cut into squares and serve with sliced strawberries, if desired.