The installation instructions for nbodykit at https://nbodykit.readthedocs.io/en/latest/ recommend use very old and unsupported versions of some Python packages (as well as unsupported versions of Python).
However, the code itself is better than that, and seems to work with recent versions of Python.
Unfortunately, nbodykit and several of its dependencies are not available through conda.
Here is now to set up a conda environment with nbodykit, using modern versions of components, and using conda as much as possible.
# Use mamba instead of conda, if you have it; the solver is faster.
conda create -n for-nbodykit -c conda-forge numpy scipy astropy pyerfa mpi4py six pandas dask cachey numexpr corrfunc sympy pip ca-certificates certifi cython compilers mpi mpi h5py halotools fitsio attrs coverage iniconfig pluggy pytest
conda activate for-nbodykit
pip install nbodykit
Note that the pip install nbodykit will also install several other Python packages; these are all the ones that nbodykit needs that are not available through conda.