Using enlarging lenses for larger negatives than they were designed for sometimes works after a fashion at smaller print sizes. Ive cheated by using a 75/4 EL Nikkor to make 8 x 10 prints from 6 x 7cm negatives, but I cant increase the magnification much larger before the corners darken too much or get cut off.
The original 150/5.6 and the newer 150/5.6A EL Nikkors are specifically made as 4 x 5 format lenses. At smaller print sizes the lens might see the entire image rectangle and project it onto enlarging paper, but the quality of the projection of the corner region of the negative might lack the definition demanded for excellence. The corners might also display some light falloff as print size is increased.
According to the Nikon data I have, the original 150/5.6 projects 54 degrees and will cover a negative of up to 190mm diagonal.
The newer 150/5.6A (f = 149.6mm) projects 51 degrees and covers a maximum film diagonal of 180mm.
The diagonal of the image rectangle of a 5 x 7 negative is about 210mm, but can vary depending on the dimensions of the film window for a particular make of film holder.
You could try the lens you have to see if makes acceptable prints at the magnification you want. The 180mm and 210mm EL Nikkors (both versions) are specifically designed as 5 x 7 enlarging lenses and will make excellent enlargements over their intended 2X-4X(optimum)-8X magnification range. Most lenses of 180mm to 210mm are designed for the 5 x 7 format.