What are the setting parameters of Nikon D90 outdoor portrait shooting?

Unless you are using manual gear (if you are not an expert, you'd better use automatic or aperture priority mode). The camera will automatically give the appropriate parameters according to the ambient lighting. Because the aperture determines the depth of field in the portrait, you need to set the aperture according to the depth of field, and the camera will automatically give the shutter data.

Unless the light is particularly poor, sensitivity is generally not needed.