In a medium mixing bowl, combine the Greek yogurt, creamy peanut butter, honey, and vanilla extract. Mix until smooth and well combined.
Stir in the mini chocolate chips and chopped peanuts, if using.
Line an 8x8-inch baking dish with parchment paper, leaving some overhang for easy removal.
Pour the yogurt mixture into the prepared baking dish and spread it evenly with a spatula.
Freeze for at least 4 hours or until firm.
Once frozen, lift the bars out of the dish using the parchment paper. Cut into squares or rectangles.
Serve immediately or store in an airtight container in the freezer for up to 2 weeks.