Identify your goal: roasted flavor (stuffing, topping, charred strips) or sauce/base flavor (blended into salsa/crema).
Pick the closest match from the table: Anaheim (closest fresh), Pasilla (best smoky earth), New Mexico (mild chile), or Bell+smoked paprika (texture).
Swap using the ratio. If your substitute is hotter, seed it and use the smaller ratio; if it’s milder, you can add a pinch of extra smoked paprika or salt.
If the pepper benefits from char, roast under high heat until blistered, then peel and slice before using in your dish.
Taste at the end and adjust: a small squeeze of lime or a touch of vinegar can brighten sauce flavors when the substitute is more muted.