  Recent analysis of the second data release of Gaia has revealed a number of
new stellar streams surrounding the Milky Way. It has been suggested that one
of these streams, Gj\"oll, is associated with the globular cluster NGC 3201,
but thus far the association has only been based on kinematics of the stream
stars. In this work we identify five likely stream members in the Gaia data
that are bright enough for high-resolution spectroscopic follow-up with the
Harlan J. Smith telescope at McDonald Observatory. One star is ruled out as a
member based on its radial velocity. Abundance analysis of the remaining four
kinematic members reveals a good chemical match to NGC 3201 for two of the
stars, driven by their similar Al and $\alpha$-element abundances. Of the
remaining two, one shows no chemical similarity to NGC 3201 and is likely an
unassociated Milky Way halo field star, while the other exhibits a similar Al
abundance but has somewhat lower $\alpha$-element abundances. The chemical
tagging of stars in the Gj\"oll stream to NGC 3201 confirms this association
and provides direct proof of the hierarchical formation of the Milky Way.
