Heat oven to 325°F. In large bowl, mix popcorn, pretzels and cheese-flavored snacks.
In small saucepan, melt butter over low heat. Stir in lemon pepper seasoning, oregano, chili powder, garlic powder and onion powder. Pour butter mixture over popcorn mixture; stir gently to coat. Spread mixture in ungreased 15x10x1-inch pan.
Bake 10 to 15 minutes, stirring once. Cool completely, about 30 minutes. Store in airtight container.