  Measurements of quarkonia isolation in jets at the Large Hadron Collider
(LHC) have been shown to disagree with fixed-order non-relativistic quantum
chromodynamics (NRQCD) calculations, even at higher orders. Calculations using
the fragmenting jet function formalism are able to better describe data but
cannot provide full event-level predictions. In this work we provide an
alternative model via NRQCD production of quarkonia in a timelike parton
shower. We include this model in the Pythia 8 event generator and validate our
parton-shower implementation against analytic forms of the relevant
fragmentation functions. Finally, we make inclusive predictions of quarkonia
production for the decay of the standard-model Higgs boson.
