  Bilayer graphene with small internal twist angles develops large scale
moir\'e patterns with flat energy bands hosting both correlated insulating
states and superconductivity. The large system size and intricate band
structure have however hampered investigations into the properties of the
superconducting state. Here, we use full-scale atomistic modeling with local
electronic interactions and find a highly inhomogeneous superconducting state
with nematic ordering on both the atomic and moir\'e lattice length scales.
More specifically, we obtain locally anisotropic real-valued d-wave pairing
with a nematic vector winding throughout the moir\'e pattern, generating a
three-fold ground state degeneracy. Despite the d-wave nature, the
superconducting state has a full energy gap, which we further tie to a
{\pi}-phase interlayer coupling. The superconducting nematicity is easily
detected through signatures in the local density of states. Our results show
not only that atomistic modeling is essential for twisted bilayer graphene but
also that the superconducting state is necessarily distinctly different from
that of the high-temperature cuprate superconductors, despite similarity in
electronic interactions.
