Lightly grease a 8x8 or 9x9 square pan.
Pour chips into a microwave safe dish. Cook until melted, stirring every 30 seconds (mine took 90 seconds). Stir in peanut butter and stir until smooth.
Add cereal and marshmallows to a bowl. Pour in the melted white chocolate and peanut butter mixture. Stir. Add mini chocolate chips and mix until combined.
Pour into prepared pan and lightly press until evenly spread. Resist the temptation to press down firmly. Allow to set about an hour, turn out onto a cutting surface, and cut into 1 inch squares.