Posting this just in case someone else is having the same problem.
I installed a brand new Nest Doorbell Wired Gen 2 and my mechanical chime stop working.
The doorbell was working fine and streaming fine. Phone support took me through trouble shooting steps and we got no where.
Noticed that the transformer was only 16V 10VA, so went and bought a 16V 30VA transformer from Home Depot.
Installed it and chime is back working even better than before.
