A. Most canned green chiles are Anaheim chilies, not jalapeños. You may see them also referred to as New Mexico chilies, although that is incorrect; real New Mexico chilies are a separate variety that are hotter than Anaheims.
Anaheims aren’t as hot as jalapeños, but you may substitute them if you can’t find fresh, canned, or jarred jalapeños. Because Anaheims are milder in flavor, you will have to taste as you season to make sure you get the degree of heat you want in the dish.
Also something to keep in mind: Mild can be delicious, but if you're going for a jalapeño kick, you'll want to buy something hotter. Since several brands come in mild and hot varieties, opt for the hot version to come closer to jalapeño flavor.