How to coat baking sheet without any oil, cooking spray, or butter?

Place the tenders on a cooling rack and place the rack on your sheet pan. The rack will allow air circulation around the tenders allowing them to get crisp both top and bottom. The tenders will be less likely to stick because they will be cooking with a dry heat and any grease will not pool under them directly but on the sheet pan below.

Parchment paper.

If you have bacon, rub it on the sheet... the faster and harder you rub, the more bacon fat will melt.

Assuming that you are just lightly coating the pan, no calories would be transferred, regardless of what lubricant you use.

You could coat the chicken with mayo as well.

Parchment paper will work or you can use a non-stick pan. If you don't have either, you could always wash the pan you heat them in.

I guess you don't realize that olive oil also has calories. More of them, in fact, since butter also contains water and dairy solids while oil is just, well, oil.

However, butter is probably going to burn when used on a baking sheet. I would use nothing at all, or some tin foil, and live with a little sticking.

Any oil will work, even using butter to lightly grease a baking sheet is not going to add that many calories. Live a little.