Pour milk into a microwave-safe measuring cup; microwave on high for 1 minute, until milk is very hot but not boiling.
Remove and add chai tea bag and let steep for 20 minutes, pressing bag gently with a spoon to release flavour.
Remove and discard tea bag; chill chai-infused milk for 10 minutes.
In a blender, combine frozen bananas, Splenda Sweetener, yogurt, ice cubes, and chai-infused milk. Process mixture until smooth, stopping occasionally to scrape down sides of blender.