In a large bowl, sprinkle the gelatin over 1/2 cup of the milk.
In a small saucepan, cimbine the remaining 1/2 cup milk with the sugar and bring to a boil over high heat. Stir until dissolved and then pour the hot mixture in the bowl with the gelatin and milk. Whisk until the gelatin is completely dissolved (this part is crucial because you don't want little chunks of undissolved gelatin to be mixed throughout the final product. Not tasty, trust me).
Whisk the yogurt into the gelatin mixture. Whisk in peppermint extract and a few drops of the neon green food coloring until you've reached your desired color.
Using an ice cream maker, freeze the mixture according to the machine's directions. I had the mixture in mine for about 25-30 minutes for a nice creamy, solid texture. About 5 minutes before you're ready to stop the machine, add in the chocolate chips. Serve immediately.