In a heavy bottomed medium sauce pot, bring milk and cream to a simmer. Add chai tea bags, cover pot, and allow to steep for 30 minutes. Strain and discard tea bags.
In a large bowl, whisk together brown sugar and egg yolks. Whisk until mixture has thickened. Add chai infused milk mixture, espresso and bourbon. Whisk to combine.
In a separate bowl, whisk egg whites with a hand mixer. Once mixture is foamy, slowly add granulated sugar. Whip to medium-stiff peaks. Add egg whites to eggnog mixture. Whisk to combine.