Here below is my work around:
1 - Under linux, I created a symlink link like this
ln -s ../timeseries/ timeseries
2- In my notebooks, I add this cell (before I import my own modules (i.e timeseries in my case))
# hide
# Only for Windows users because symlink to `timeseries` folder is not recognized by Windows
import sys
sys.path.append("..")
This way, I’m able to store my notebooks in the nbs folder, and everything works well. You can check out one of my notebooks in my repo (e.g. 81_timeseries_core.ipynb in the import section on top)
I hope you will find it helpful