Add the tequila, Chartreuse, and whatever amer (or amaro) you are using, and the bitters to a mixing glass.
Fill the glass two-thirds with ice and stir briskly for 15 seconds.
Strain into a chilled coupe glass. Point the colored side of the orange twist toward the top of the drink and squeeze to express the orange oils in the peel over the top of the drink. Drop the twist into the glass.