I think the issue the way you tackle the claim, you can just all in and claim it was a battery leakage and imply you do not think its anything different and should be able to claim regardless under the warranty, whereas if you hint that it could be something else, then really its a get out for nintendo to claim its not their fault and charge you basically 100 to swap out/trade to a new console, comes down to what you have done already, if you have entered the switch serial and logged any info etc could well be screwed as maybe implied its a unknown issue, they could easily turn around and nix the claim, saying your at fault for damage caused, you could be able to find in local walmart or similar something that can test for acidity etc ,and that maybe can confirm if the substance is acid based ala battery, if that tests negative then could well be a sticky candy, soda, reaction to surface of the table, or 101 other things, a cheap test that such as used for fish tanks might work, need to at least have some more knowledge before trying to take on a claim IMO