Was up in Yosemite in January; not with a Tesla, though. Snow tends to show up in a hurry in the winter. You don't want to get caught out. Spend the money on some chains and, ahead of time, figure out how to put them on. Better safe than sorry.
You didn't say what kind of tires you're running on. SR and LR Teslas come with All Seasons which aren't total $BS in snow, generally. Any "P" variant comes with Summer Tires which is like putting grease on the wheels - they're nearly useless in the snow, never mind being hard bricks with no traction once the temperature gets below 45F or so.
(Speaking as an Northeast Coaster who grew up in serious snow and other forms of non-liquid precipitation. For those who live in the lowlands of CA, all that snow up there, if one hasn't driven in it before, may come as something of a shock. Every turn turns into a four-wheel drift, no matter how slow...)