Place the mashed avocado in a food processor and blend until very smooth.
Add the chocolate protein powder (plus 2 tablespoons) and vanilla extract to the processor and blend until fully combined and smooth.
Put the milk chocolate chips in a microwave-safe bowl and microwave in 20-second intervals, stirring between each, until fully melted (about 1½ minutes total).
Pour the melted chocolate into the processor and blend until the mixture is smooth and homogenous.
Transfer the truffle mixture to a medium bowl, smooth the top, cover with plastic wrap, and refrigerate for 2 hours to firm up.
Line a large plate with parchment or wax paper. Drop the natural peanut butter onto the paper in 1-teaspoon-sized dollops and place the plate in the freezer while the truffle mixture chills.
Place the crushed banana chips on a shallow plate or bowl for rolling, and line a cookie sheet with parchment or wax paper for finished truffles.
Scoop about 1/2 tablespoon of the chilled truffle mixture and slightly flatten it in your palm. Put one frozen peanut butter dollop in the center, top with another 1/2 tablespoon of truffle mixture, and roll to enclose the peanut butter. Repeat to make remaining truffles.
Roll each truffle in the crushed banana chips until coated, place on the prepared sheet, and keep refrigerated until serving.