Serial COMMS on Standalone Atmega 328p

Good Day people :), I build a project using two Arduino Uno's as my development boards. The Master 328p communicates with a Nextion Screen via the Hardware Serial pins (1 and 2), The Master and Slave also communicates via I2C (pins A4 and A5). All worked fine using the Uno Boards. The problem I have is now when I build my proto PCB all works well except for the Serial comms from the Master to the Nextion.

When using TX and RX pins on a standalone 328p to communicated serially can I directly connect the Nextion's TX and RX pins or is there other hardware required for Serial comms on the standalone 328p?

Thanks

Sorted Thanks. Forgot a crucial bridge on the PCB :-[