Working with NIR data from many different sources is not easy and we have to check the data, make some groupings and to create different products in order to take certain ranges, eliminate bias and curvature, check for different math treatments to see which one makes the model more linear, etc.
Neural Networks Models deal with all these but is more complex and unknown. It requires also for a lot of data.
But how it works?: Read this link to know how it works and how can you build these models with R.