Superconductivity with a remarkably high Tc has recently been observed in hole-doped NdNiO2, a material that shares similarities with the high-Tc cuprates. This discovery promises new insights into the mechanism of unconventional superconductivity, but at the modeling level, there are fundamental issues that need to be resolved. While it is generally agreed that the low-energy properties of cuprates can, to a large extent, be captured by a single-band model, there has been a controversy in the recent literature about the importance of a multiband description of the nickelates. Here, we use a multisite extension of the recently developed GW+EDMFT method, which is free of adjustable parameters, to self-consistently compute the interaction parameters and electronic structure of hole-doped NdNiO2. This full ab initio simulation demonstrates the importance of a multiorbital description, even for the undoped compound, and it produces results for the resistivity and Hall conductance in qualitative agreement with experiment.