Bring cream cheese to room temperature. Melt chocolate in the microwave or in a double boiler. With a fork mix cream cheese and melted chocolate together until smooth. Place in the fridge for a bout 15 minutes if the mixture is to warm to roll. Roll the mixture into 12 truffles.
Mix cocoa nib and chili powders together. Roll the truffles in the powder mix, and refrigerate for 15 minutes. Put powder mix aside.
Heat oil in a small skillet over med-high heat. Cut tortillas in a circle slightly bigger than the top of your shot glasses. Fry tortillas, folded in half and keeping the shape with a fork by pressing down, in oil for about 20 seconds per side until firm a bit. Press with paper towels to remove excess oil.
Wet the shot glass rim with lemon juice and dip the rim of the shot glass in the remaining powder mix.
Mix mezcal and tomato juice together. Pour 1.5 oz of the mix into each glass. Set aside
For each tortilla spread guacamole on top, add an onion stick, then a truffle, and sprinkle with cilantro.
Place topped tortilla on top of each filled glass. Serve. Makes 12 appetizers.