Using chopsticks in a Mexican restaurant would generally not be considered rude, but it may be seen as unusual or out of place. Mexican cuisine traditionally relies on utensils like forks, spoons, and knives for eating. However, in modern times, cultural diversity and globalization have led to the acceptance of various dining practices. Many restaurants are accommodating and provide alternative utensils upon request, including chopsticks.
If you prefer using chopsticks due to personal preference or cultural reasons, it's always a good idea to politely ask the restaurant staff if they can provide you with a pair. They will likely be happy to assist you. Ultimately, the most important thing is to enjoy your meal and show respect for the restaurant's customs and traditions.