Nexus - short for Nextion Upload Script - is a python script that allows the upload of TFT files to a Nextion screen over serial. Unlike most other scripts out there this one uses the Nextion Upload Protocol v1.2. This is the newer version used by the Nextion Editor itself that allows skipping parts of the TFT file if those have not been modified.
Nextion never published any details about this newer version but it's been reverse-engineered and documented.
Complete documentation of the command line options is available using
python Nexus.py -h
To upload a file at 512000baud/s type
python Nexus.py -i PATH_TO_YOUR_TFT_FILE -u 512000
The script will automatically scan all available ports for a Nextion screen. You can manually specify a port using -p PORT. To list all available ports use
python Nexus.py -l
If you get an error like Expected acknowledge (b'\x05'), got b''. it means that Nextion did not respond as expected or not at all. Most likely reasons are a wrong model (TFT file has been compiled for another model) or a too high baudrate.