  Anomalously high nitrogen-to-oxygen abundance ratios [N/O] are observed in
globular clusters (GCs), among the field stars of the Milky Way (MW), and even
in the gas in a $z\approx 11$ galaxy. Using data from the APOGEE Data Release
17 and the Gaia Data Release 3, we present several independent lines of
evidence that most of the MW's high-[N/O] stars were born in situ in massive
bound clusters during the early, pre-disk evolution of the Galaxy.
Specifically, we show that distributions of metallicity [Fe/H], energy, the
angular momentum $L_z$, and distance of the low-metallicity high-[N/O] stars
match the corresponding distributions of stars of the Aurora population and of
the in-situ GCs. We also show that the fraction of in-situ field high-[N/O]
stars, $f_{\rm N/O}$, increases rapidly with decreasing metallicity. During
epochs when metallicity evolves from $\rm [Fe/H]=-1.5$ to $\rm [Fe/H]=-0.9$,
the Galaxy spins up and transitions from a turbulent Aurora state to a
coherently rotating disk. This transformation is accompanied by many
qualitative changes. In particular, we show that high N/O abundances similar to
those observed in GN-z11 were common before the spin-up ($\rm [Fe/H]\lesssim
-1.5$) when up to $\approx 50\%-70\%$ of the in-situ stars formed in massive
bound clusters. The dramatic drop of $f_{\rm N/O}$ at $\rm [Fe/H]\gtrsim -0.9$
indicates that after the disk emerges the fraction of stars forming in massive
bound clusters decreases by two orders of magnitude.
