  We report accurate quantum Monte Carlo calculations of nuclei up to $A=16$
based on local chiral two- and three-nucleon interactions up to
next-to-next-to-leading order. We examine the theoretical uncertainties
associated with the chiral expansion and the cutoff in the theory, as well as
the associated operator choices in the three-nucleon interactions. While in
light nuclei the cutoff variation and systematic uncertainties are rather
small, in $^{16}$O these can be significant for large coordinate-space cutoffs.
Overall, we show that chiral interactions constructed to reproduce properties
of very light systems and nucleon-nucleon scattering give an excellent
description of binding energies, charge radii, and form factors for all these
nuclei, including open-shell systems in $A=6$ and 12.
