Polished nickel and chrome are fairly similar finishes so either would work with your appliances, sink and hardware. My preference however is for the luster of polished nickel.

This is 100% preference. And you may not even have a choice if the faucet you fall in love with only comes in a certain finish. If the sink is under mount (mounted under the counter) I would have the faucet match the hardware since you're not even going to see the sink from a distance. If it's an apron front, I would probably match the faucet to the sink. Also, brushed nickel tends to hide water marks compared to a shiny finish. So that may play apart in your decision making.

I am putting in a kitchen with off white cabinets, stainless appliances /sink and bronze hardware/chandelier/lighting fixtures. Two designers at different shops have suggested as the pro above did that I buy my faucet to match the hardware and not match it to the stainless sink . Both said as the sink is under mount and won't be seen unless looking into it the faucet will look great matching the rest of the bronze.

What if the sink is a top mount? I have been trying to figure this out all day. I'm putting in off-white cabinets, black appliances and live edge heart pine counters. Down to the sink, faucet, and drain. The drains that come in black tend to chip, so I am thinking brushed nickle faucet and drain, but I can't decide!