(at least) Hertz is offering chains (at quite a price..)*).
Note that winter tyres ("M+S") are required in winter conditions (fine starts at 60EUR), also some streets (esp. in AT) might require chains.
*)
https://www.hertz.com/rentacar/reser...D=SKI&EOAG=MUC
Noticing one cannot book this service via Internet (ridiculous).