On mac, chrome is not centered, and shifted to the right. How to fix it?

It looks to me like it's "not centered" because your window is actually much wider than your display screen, and extends to the right of the screen. (I think you'll find that within the window, the display of the content actually is centered.) I have seen this on rare occasion. I don't know a fix that's elegant, but you should be able to fix it in this inelegant way: Click and drag the left edge of the window to reduce the width of the window; then, grab the window header to move the whole window back over to the left, hopefully revealing the right edge. If the window is still too wide, repeat the operation until it fits on your display screen. Then size the window to your preference.