Simply install the kernel for the Jupyter environment following the official guide: https://github.com/WolframResearch/WolframLanguageForJupyter
then WL would be there (tested on macOS with Anaconda Python 3.7.3):
A noting caveat is that the auto-completion is missing.
Environment info:
conda version : 4.6.14
conda-build version : 3.17.8
python version : 3.7.3.final.0