Pour 1 cup of Nux Alpina walnut liqueur into a shallow plastic container. Mix in 1 cup of simple syrup and the soy lecithin. Pulse with a hand immersion blender until thoroughly mixed. Chill for 2 hours.
Put tequila, poblano puree, lime juice and remaining walnut liqueur and simple syrup in a cocktail shaker filled with ice. Fill an old-fashioned glass with ice. Shake and strain the cocktail into the glass.
Froth the surface of the chilled walnut liqueur mixture with the hand blender repeatedly until sudsy bubbles start to form.
Scoop bubbles with a spoon and layer on top of the cocktail. Gently place pomegranate seeds on top of air.