This still sounds like COVID-19 fallout, although there's also the demographic of the customer base. I read 'fast casual' as just the next step up from 'fast food' like McD's, BK, and the like. Prices are rising so many in their customer base are saying 'no more $10 Big Mac for me.'
We already see that Nixon switched two of his burger places to Taco and 'expensive alcoholic drinks' places. That may still hit the 'casual' side of the demographic, but not the "fast."
Like with McD's, BK, and the like, there's probably a measure of price-point expectation in TGI Fridays and Red Lobster and other chains. Nixon's restaurants are not chains (yet). Based on the Google Reviews of Tequila Taco so far, all though people mention it being a bit pricey, they seem to feel that they are getting what they are paying for. As long as people feel that way, they will keep returning.
He's also in Denver, not New York/New Jersey.
