Pay social security in Beijing for 2 years and transfer to Nanjing account. The company in Nanjing has paid social security for three months. Can I buy a house in Nanjing under such circumstances?

Not counting the transfer from other places, you have only been in Nanjing for three months, and you are not qualified. You have to pay 12 months locally.

If the transfer is regarded as the same, then the purchase restriction is meaningless. The phenomenon of participating in insurance is very common now. People who want to buy a house (of course, the age conditions meet the local permission to transfer) will transfer to a certain place as soon as the insurance takes effect. The loading time is also included. Then the waiting period is less than two months.