Hi,
I hold a law degree with a 2:2 and a LLM with Merit, both from UK universities. I am a qualified lawyer and I have around 5 years of experience mainly in antitrust law.

Do I have any chances of getting admitted in unis such as NYU, Columbia, Stanford or Georgetown?

except for Stanford everything else is possible. You got great chances.

Thanks - any other suggestions?

if you are interested in antitrust law, i would also suggest UChicago.