I want to use an ESP8266 (nodemcu) as MQTT gateway but instead building a client for the same room use it as Client as well.

However after connecting NRF24 I do not know how to connect my I2C sensors because D2 is used by the NRF already.

I searched for it but did not find a clear or working information on this. So I really would appreciate someone can give me a working solution to build a gateway including I2C support with one chip (nodemcu, Wemos, ???).

Staub as below but need WiFi for Gateway function tying to use a nodemcu.

Room sensor:
Board - Arduino Nano with Shield to provide proper power and PINs
Radio - NRF24
I2C - BME280 (Temp, Hum, Pres)
I2C - tsl2561 (Lux)
PIN - Mosfet (Nightlight with little LED)
PIN - MH-SR602 (PIR/Motion)