There was a previous topic to discuss BSEC library on PIC32, https://community.bosch-sensortec.com/t5/MEMS-sensors-forum/how-to-get-IAQ-value-from-BME680-using-PIC32MX370-470/m-p/14866
You also could refer official BSEC library from https://www.bosch-sensortec.com/software-tools/software/bsec/
If your MCU part could be found in the supported list, please let me know your MCU part and compiler version, compiling options.
MCU detailed type: xxx IDE version: xxx Compiling options: xxx
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