In a large pot, melt butter over medium heat.

Once butter is melted, add marshmallows and stir to combine. Stir frequently to prevent burning, and reduce to medium-low heat if needed. Marshmallows will melt in 5-10 minutes.

Add the vanilla and chai spice blend. Stir to combine.

Remove from heat and add Rice Krispies cereal. Stir to combine completely.

Transfer mixture to a 9x13u0022 parchment lined dish (or a sheet tray for thinner Rice Krispies).

Using a wooden spoon dipped in warm water, gently spread the mixture until evenly distributed. Be careful not to press the mixture down too much into the pan as this will make the treats hard.

Add milk to a microwavable container and heat for 10-20 seconds until just warm. Do not overheat.

Pour warm milk into a bowl with Nutella and stir to combine.

Drizzle over warm Rice Krispies Treats.

Allow the treats to cool at room temperature before removing and cutting. Enjoy!