Put the fritos and the pretzels in a large ziploc bag and smash until crumbly. Set aside. Line a 9x13 inch pan or cookie sheet with foil or parchment paper. Set that aside. Put the butter, brown sugar, peanut butter and chocolate chips into the crockpot and set on high for 1-2 hours or until everything is really melted and mixes well. Stir in pretzel and frito pieces. Using oven mitts, dump the hot candy onto the lined cookie sheet and spread out with a wooden spoon. Sprinkle the peanut pieces on top. Put the pan in the fridge for about an hour, or until candy has set completely. Break into pieces, and enjoy.