Cook microwave popcorn according to package.
In a large bowl, combine popcorn and marshmallows.
Melt white chocolate chips according to melting instructions on package, and mix with popcorn mixture, until fully coated.
Spread popcorn onto sheets of wax paper, and sprinkle hot chocolate powder over the top. Don't wait for white chocolate to harden, or the chocolate won't stick.
Melt milk chocolate chips according to package instructions and drizzle over popcorn.
Allow chocolate to harden, and serve in a mug!