Tina, I found this which sounds similar. I don't know if it's possible to make a yogurt coating at home.

KITCHEN SINK SNACK MIX
Makes 24 servings

This snack mix has a little bit of everything. Corn cereal, pretzels, nuts and raisins are coated in a white chocolate and peanut butter candy.

1 cup peanut butter
1 (12 ounce) package white chocolate chips
1/2 cup butter
5 cups corn cereal
4 cups pretzel sticks
2 cups nuts, any variety
1 cup raisins
1 1/2 cups powdered sugar

Microwave peanut butter, chocolate chips and butter on high for 2 minutes, or until ingredients have melted.

In a large bowl, mix cereal, pretzels, nuts and raisins with peanut butter-chocolate mixture, until evenly coated.

Pour mixture into a large plastic (food grade) bag and add powdered sugar. Shake until coated.

Spread on wax paper to cool.