In a mixing bowl, combine the Greek yogurt, peanut butter, protein powder and chocolate chips. Stir until well combined and smooth.
Line a baking dish or cookie sheet with parchment paper, and scoop yogurt mixture into round shapes, spreading it out evenly. Stick each round with a popsicle stick.
Sprinkle the chopped mixed nuts evenly over the frozen yogurt layer, gently pressing them into the surface.
Place the baking dish in the freezer and let the yogurt layer freeze for about 2 hours or until firm.
In a microwave-safe bowl or using a double boiler, melt the chocolate chips and coconut oil together until smooth and well combined. Stir occasionally to ensure even melting.
Pour the melted chocolate mixture over the nuts, covering the entire surface. Use a spatula to spread it evenly, ensuring all the nuts are coated.
Return the baking dish to the freezer and let the bars freeze for another 30 minutes, or until the chocolate coating is firm and set.
Allow the bars to thaw for 5-7 minutes before consuming, otherwise they will be too icy and hard to eat. Enjoy!