You can add your Nibe heat pump via SG-Ready using a Shelly Plus 1 in our system.
VVM S320 / S2125 Installer Manual:
https://assetstore.nibe.se/hcms/v2.4/entity/document/875886/storage/ODc1ODg2LzAvbWFzdGVy/download/Installateurhandbuch_Luft%2FWasser-W%C3%A4rmepumpen_VVM%20S320_631802-4.pdf
You can find the instructions for wiring and activation on pages 25/26 of the installer manual.
When working with a single Shelly, you can bridge a contact to switch between both contacts open and both contacts closed (increased capacity mode, normal operation).
SMO S40 Installer Manual:
https://assetstore.nibe.se/hcms/v2.3/entity/document/877309/storage/ODc7MzA5LzAvbWFzdGVy
The wiring and setup instructions start on page 26.
After connecting the 2 AUX terminals to the Shelly input and a cable to GND and the Shelly output, SG-Ready must be assigned to the two AUX terminals in menu 7.4.
Afterward, SG-Ready can be activated in menu 4.2.3.