What is the serving size and how much sodium is in a serving?

I only buy the whole chilies. Nutrition facts as stated by Ortega: serving size 30g(1 pepper), sodium 60mg, 3%.

Do the mild diced chiles have seeds in the can?

My last 3 orders were for the whole chiles. I stopped buying the diced chiles, not only because it had seeds, but the can contained those black tiny pieces of the burned outer layer.

Purchased this 12 pk last 4/28/20 at $11.76 and now same is listed at $41.50 is this correct?

Take look to see if they are toasted chili skin.

how do I get the chilis that are whole?

You can get them whole and fresh when they are in season. Usually in the fall for Anaheim chili's. Or you can get them in cans whole, roasted and peeled (the larger cans. Fresh is best but the canned ones are good too.