Combine sweetened condensed milk, matcha, and salt.
With electric mixer on medium-high speed, whip heavy cream to soft peaks, about 2 minutes. Whisk one-third of whipped cream into sweetened condensed milk mixture. Fold remaining whipped cream into sweetened condensed milk mixture until incorporated.
Fold in the oreo cookies.
Place in airtight container and freeze until firm, at least 6 hours or up to 2 weeks. Serve.