Something to remember about authentic Mexican cuisine is that it's largely peasant-based, using ingredients that are readily available in Mexico. An awful lot of Mexican cooking is about the myriad sauces, which are used to vary a diet in which the main ingredients often show up every day. You can use most of the sauces equally well on pork, chicken or beef, to make enchiladas or casseroles, etc. The technique of enchiladas in mole and enchiladas in green sauce is very similar, but the taste certainly isn't!
Mexican recipes can look challenging because many use lots of ingredients. Originally, this was pretty labor-intensive cooking. Poor women usually had kids or extended family members who helped in the laborious effort; middle and upper-class women had cooks who did all the work! Fortunately for Mexican cooks everywhere we now have blenders and food processors available that make preparing traditional sauces a snap! So don't be intimidated by recipes with many ingredients -- modern appliances make them much easier! Pretty much all of the cooked sauces freeze well, too, so make a lot and freeze some for future use. Like many complex sauces, most of them improve after being refrigerated or frozen so the flavors really meld together. That means you can make most of these sauces ahead of time and they'll be even better than if you make them "just in time."
There are many convenience products available (especially in Mexican markets) than can shorten cooking times. There are excellent ground chiles or chile pastes, for example, that will save you having to grind your own. Very good prepared moles, pipianes and adobos are available off-the-shelf that just need some "doctoring" at home to make them perfectly delicious! Many recipes call for ground nuts or seeds for flavor and thickening, but you can use readily available nut flours, nut butters and tahini instead, to equally good effect. Tomato-flavored chicken broth is used in many Mexican dishes, and Knorr and Maggi have it in instant form. The Knorr Mexican shrimp broth (in powder or cubes) is spicy and makes a great base for many fish/seafood dishes. As well as Mexican cooking, I use it to make Creole jambalaya! It would probably be a good ingredient in a bouillabaise or cioppino, too! Once you become familiar with the Mexican food aisles you'll probably think of numerous uses for some of the ingredients! Almost all ingredients you can't find locally are now available online, so don't let a lack of Mexican ingredients in your area stop you! (If you can't find Mexican chorizo in your area, it's very easy to make at home with a food processor -- another item you can make in quantity and freeze in individual-use portions for future use.)
Finally, feel free to improvise once you've found a recipe you like. Mexican cooks do all the time! There aren't too many hard and fast rules. Obviously, Puebla-style mole must include dark chiles and unsweetened chocolate, but you can play around with the many spices and thickeners. No two cooks in Mexico make it identically! Pipián means a sauce is based on green pumpkin seeds or nuts, but, again, you can vary the seasonings to your taste. And so on! Mexican cooks pride themselves on their creativity in improving traditional recipes, and so should you!