Pixinsigth has great tools for creating mosaics. One such tool is the PhotometricMosaic script by John Murphy. You prepare linear images with scripts ImageSolver, MosaicByCoordinates and TrimMosaicTile and then create the mosaic using script PhotometricMosaic.
Using these tools with AutoIntegrate you first need to run a workflow which creates integrated linear images Integration_[LRGBHSO] for separate color channels data or Integration_RGB for OSC data. You can then create a mosaic for each channel or for OSC data.
Once you have the mosaic tiles you can load them into PixInsight with names Integration_[LRGBHSO] or Integration_RGB_color. You can then create the final image using the AutoContinue button.