Use Blynk on all ESPs, Bridge to share the data, and run the Nextion code on one of the ESPs.
And your ‘missing’ sketches …
Or use one ESP for everything… Study this and convert for ESP8266 and your sensor…
Otherwise If the ESP for the Nextion is non-Blynk and can use a virtual pin for an extra serial port then you can try EasyTransfer between the Blynk ESP and the Nextion ESP
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