Toast the nuts by placing them in a dry skillet set over medium-low heat for about five minutes, or until they begin to look lightly browned and smell toasty. Keep a close eye on them as they can burn quickly. Then move them to a tray lined with parchment paper to cool.
Microwave the white chocolate chips in 15-second bursts, until melted enough to stir smooth.
Mix the toasted nuts into the white chocolate and spread the mixture onto your lined tray in one even layer. Place in the freezer to set.
Use a blender to mix the allulose, almond milk, and Keto Chow until the allulose is dissolved, and the Keto Chow is well incorporated.
Add the heavy cream and the pistachio extract if using; blend briefly until combined and frothy. If you blend too long, you will turn the cream into butter.
Transfer to your ice cream machine and churn according to the manufacturer's directions.
While the ice cream is churning, break the chocolate-covered nuts into individual pieces and add to the ice cream mixture. Some machines can mix in add-ins for you. If yours does not, fold them into the ice cream when you transfer it.
Transfer the ice cream to a container and freeze for at least four hours.
Keep in an airtight container in the freezer for up to two weeks for best results.