SCF energy of the NWChem sample (H2O)

Since you re using Ubuntu 18.04, my suggestion is to try the packages available from the github site, instead of try to compile the source code.
Here are the installation instructions

sudo apt -y install mpi-default-bin libgfortran4 libopenblas-base \
libopenmpi2 libscalapack-openmpi2.0 openmpi-bin libquadmath0 \
libfabric1 libhwloc5 libibverbs1 libpsm-infinipath1 \
openmpi-common libhwloc-plugins libnl-route-3-200 \
ocl-icd-libopencl1  librdmacm1

wget https://github.com/nwchemgit/nwchem/releases/download/6.8.1-release/nwchem-data_6.8.1+133+gitge032219-2_all.ubuntu_bionic.deb

wget https://github.com/nwchemgit/nwchem/releases/download/6.8.1-release/nwchem_6.8.1+133+gitge032219-2_amd64.ubuntu_bionic.deb

sudo dpkg -i nwchem_6.8.1+133+gitge032219-2_amd64.ubuntu_bionic.deb \ 
nwchem-data_6.8.1+133+gitge032219-2_all.ubuntu_bionic.deb