Since you shoot Nikon, many of the DX bodies have the internal 1.3X Crop capability....it is called "Image Area" in the menu - it works better than teleconverters, there is no extra glass in the path, no light loss. It is a crop, but in the field it allows me to fill the frame with the push of a re-assigned button, and if well taken, no loss of detail. I have a number of TC's that I skip over because of this feature. You won't (opinion) be happy with a TC on the 55-300 (had it, tried it), at best you might get away with a quality 1.4, but would still expect less than stellar results , 1.7 very doubtful results, 2X, "fogedaboutit".... and many (like the 55-300) will not AF with the bigger TC's.

My$.02

I bought a Kenko 1.4x TELEPLUS PRO 300. Tried it with my Nikon AF-P Nikor 70-300 DX lens. Took a few test shots at max zoom using a tripod. Auto-Focus works, but very soft images. Probably should have returned it. I didn't think, I paid all that much for it, but just reviewing my Amazon order, I see I paid $139 for it. Don't waste your money. Pictures OK for desktop viewing, but not much more.
Not seeing how to attach a photo in reply.
OK - can do it in edit, but had to save as a smaller file to get it to upload.