In a medium microwave safe bowl, microwave the cream cheese for 10 seconds. Mix in the sugar until it forms a paste.
In a separate bowl, mix together the heavy cream, milk and peppermint extract.
Slowly (1 Tbsp at a time) mix the cream mixture into the sugar mixture until the sugar is dissolved. Mix in the green food coloring until it reaches your desired color.
Pour the mixture into your Ninja Creami pint container. Cover and freeze for at least 24 hours.
In a small microwave safe bowl, microwave the chocolate chips and coconut oil in 30 second intervals, mixing until smooth.
Line a plate with parchment paper. Pour the melted chocolate on top, then place in the freezer until ready to use.
Place the frozen Ninja Creami pint in the Ninja Creami machine and set to ice cream.
Make a hole in the center of the ice cream that extends all the way to the bottom of the pint. Break up the hardened chocolate and place in the hole. Set the Ninja Creami to mix-ins.