After a few versions, I think this one is best:

Nonfat Chai Latte Mix:

2 cups sugar
2 1/2 cups unsweetened powdered instant tea
1 1/2 cup packed brown sugar
2 cups nonfat dry milk powder
3 teaspoons ground cinnamon
1 teaspoons ground nutmeg
3 teaspoons ground cardamom
3 teaspoons ginger

Put it all in a mixer or food processor, whirl together.

Do not attempt to mix it by hand, as then you end up with brown sugar boulders, it needs the mixer or for processor, or even a blender will do, I bet!

The added ginger gives it a bit of zip, yummy!

And if you attempt this at home -

DO leave the cover on the food processor/mixer/blender for a minute or so after pulverizing the mix - otherwise cuts rises! Yummy, task dust, but dust nonetheless!