Here's my best effort! I too have never processed a narrowband image before and I'm still learning pixinsight. It continues to amaze me how powerful this software is. Coming from photoshop though I do miss a few features! I thought I'd do something interesting with the narrowband data to see if I could produce a unique colour of the target. I found the most interesting to be OSH because you have the blue nebulosity contrasted against the red glow from the star Navi. Wish I could've extracted more of the fainter data in the HA filter but I'm happy considering I'm still learning!
Steps:
Combine as OIII-SII-HA:R-G-B (pixelmath, no math operators, raw images used)
Autocolour script to balance the available data with a black background
Histogram Transformation - convert to non-linear data and align RGB channels
Range select - white for deep space background
Multiscale Liniar Transform noise reduction
Masked stretch to bring out that nebulosity
Curves transformation
ACDNR - more noise reduction
Local Histogram equalisation (a few runs at a minor strength)
SCNR (green) - remove minor green cast over image and stars
TGV Denoise (strength 2) - smooth out background noise that was creeping in
Colour Saturation - Push the blues to balance with the red from the Navi
EZ Star Reduction
Local Histogram equalisation
Final curves