So we see the small hyperechoic "nodule" in the upper pole cortex right? Is it a cyst?

Answer: Renal junctional parenchymal defect

A small round or triangular hyperechoic area, classically in the upper pole cortex of the kidney.

The kidney forms from renal lobules right? Well when one doesn't complete fuse, you can have a small insinuation of fat, ie what we see here. it is a totally incidental findings.