In American English, "Chili" is the most common spelling for the spicy peppers as well as the stew. In Spanish speaking countries and regions of the US, "chile" is the most common variant. The Brits stuck with the ‘original’ spelling of “chilli”, while Latin and Spanish areas modified the spelling to better suit their language, so it became “chile” (one “l” and an “e”). Americans tend to adopt and then shorten British English, so most of the country opted for “chili” (one “l” and an “i”). The Spanish-influenced American Southwest, however, has stuck with “chile.” and thus the American Queso dip is "chile con queso" They are interchangeables in the USA so both can technically be used I guess. Chile is also a south American country as well lol. But, to prove the point : The Chile Pepper Institute (https://cpi.nmsu.edu/ ), Chile Pepper Festival (https://www.chilepepperfestival.org/), Hatch Chile Festival (https://www.hatchchilefest.com/) , The Great Chile Book (https://www.amazon.com/Great-Chile-Book-Mark-Miller/dp/0898154286) and The Whole Chile Pepper Book (https://www.amazon.com/Whole-Chile-Pepper-Book/dp/0316182230)
If you are trying to make a dry chili POWDER to add to your chili recipe, I suggest reading the ingredients on the back of your favorite chili powder and then purchasing the WHOLE spices listed there.
Whole spices toasted and then ground provide tremendously more flavor than any factory ground spices.
I agree with the dried peppers comments - but don't soak them if you are making a chili powder. Simply toast the whole chiles in a dry skillet, let them cool and remove the seeds, stems and inner white ribs of each pepper. Grind the toasted skins into fresh single variety chili powder powder.
How to pick a chile variety? Research! https://www.amazon.com/Great-Chile-Book-Mark-Miller/dp/0898154286
High quality dried garlic and onion powders are also necessary for a good chile powder. Penzey's is a good source for those. Buy only what you need as spices lose their pungency as they age.
You'll most certainly need: Cumin and Corriander seeds. We usually start with a 2:1 ratio of the two for our chili powder mixes.
Have fun with it, spice mixing is like art!