Currently the 15k target will simply allow us to port our game onto the Switch and make sure it's bug-free, we cannot offer Switch rewards at this time simply due to the risks involved with developing for it. Essentially, that's a promise that could get broken by unforeseen circumstances, and we don't want to be breaking promises at all.
However, if the stretch goals go well enough we will likely reward backers over a certain pledge amount with copies of the game on consoles. This may be limited by pledge order as well.(as in, the first X amount who pledged). As well as creating a new reward pledge specifically for the Switch. As I said before though, it's a risky thing for us to promise at this stage, we'll know more when/if we get the funding to develop on the Nintendo Switch.