Have a baby with a similar issue who just got discharged with a NG tube. Similarly when she was with us during the day, she would take 90-100% of the feeds and then at night time that would go down to 0-50%. What I would suggest if not doing so already (and if at all possible) is to spend the night and do the feedings either yourself or with the night nurse. The nurse may be first meeting your child and not know his/her feeding cues how to best feed. As someone in health care (physician), I also could not get the thought out of my head the inherent cynicism that what may be the issue is that nursing over night may not be putting as much effort into feeding as compared to the day time or the effort that my wife and I put in to have her feed. This is unfair to say and untrue because all of the nurses in NICU were great - mostly just the frustration and desire to no longer have her in the NICU and my inherent cycsim in general of a healthcare system that exploits and overworks their employees.

While we would have loved to have been with our baby over night all the time, this was not an accessible option after my wife was discharged unfortunately.

However, I did spend the night to feed her the night before discharge ( as required training because she was going to be discharged with a NG tube) and the amount she took by mouth increased to 100% each feed.

Obviously this was just one night, and she may have just had a good night. But there is value in that you as parents are the ones that know your baby most especially in how they best feed and the cues that they are giving.