Line a baking sheet with parchment paper.
Make sandwich crackers: spread about 1/2 tablespoon creamy peanut butter on one Ritz cracker and top with another cracker. Repeat until all 60 Ritz crackers are used (30 sandwiches).
Arrange the sandwiches on the prepared baking sheet and refrigerate until the peanut butter firms, which will make dipping easier (about 10–15 minutes).
Place 2 1/2 cups semi-sweet or milk chocolate chips in a microwave-safe bowl. Melt in 30-second intervals, stirring between each interval, until smooth.
If you want a thinner chocolate for dipping, add a small amount of butter, coconut oil, or shortening to the melted chocolate and stir until incorporated; add gradually until you reach the desired consistency.
Dip each peanut butter sandwich into the melted chocolate—fully or halfway—letting excess chocolate drip back into the bowl. Place dipped sandwiches on the parchment-lined baking sheet. Add sprinkles immediately if using.
Refrigerate the dipped sandwiches on the baking sheet until the chocolate is firm (about 15–30 minutes).