Well, this is a tough question.
Probably the best chances are in hammer throw.
In men's hammer Paweł Fajdek is our best chance for medal, even gold I would say, but - despite he won a few gold medals in world championships - he imploded awfully both in 2012 and in 2016 in the qualifications. So I hope he will hold his nerves this time. And secondly, he needs to be careful about Bence Halasz, this is a very serious contender, improving fast. So Fajdek is our biggest chance for gold - but it will not be easy at all. Wojciech Nowicki may get a medal, too.
In women's hammer Anita Włodarczyk will have a difficult task to win another medal. US throwers are getting better and better and she had some health and coaching problems, so I don't expect her to win again. Papers say that it is quite possible that she will not take part in Tokyo olympics at all. But I hope she will.
There is a chance for a medal in men's pole vault. But only Bronze, I'm afraid. Piotr Lisek was 3rd in Doha and 4th in Rio. But two medals are for Armand Duplantis and Sam Kendricks, I think, so there will be very tense fight for 3rd spot on the podium.
Women's 4 x 400m is another chance. US team are much better, but Polish quartet should be able to perform well if you compare them with the rest.
This new mixed relay is a minor chance, too. But it is hard to find two fast 400m male runners in Poland these days, unfortunately.
So these are our chances. If there will be 3-4 medals and 1 gold I would say it would be a decent result.
And now some wishful thinking - I would be superhappy if we get a medal in individual track event. The last time we got one was a long long ago. Much too long. I would be superhappy if it was men's 800 or 1500 but both Adam Kszczot (800) and Marcin Lewandowski (1500) will have a difficult task to do it. I know they have their non-olympic medals already around their necks, but in Tokyo it will be a different game, much more difficult. I'm afraid they are faster runners than them nowadays, and these faster people will not repeat the mistake many did in men's 1500 final in Rio. In a slower pace, Kszczot's and Lewandowski's chances are getting higher but I expect both 800 and 1500 finals will be superfast this time.
If Caster Semenya and a few others and some new Rusians (never heard of before) will not participate - there will be a chance for Joanna Jóźwik for a good run in 800m final if she qualifies. But she had some health problems, too and - I'm not an expert - but I think she will need to think more on her tactics if she wants to win an olympic medal.
Sofia Ennaoui in 1500 is another chance - I like her very very much, I don't know her in person obviously, but she appears to be a very warm and funny person, really dedicated to her training. So I'm a big fan of hers. But her problem is she is competing in a time when the level of women's 1500 is really high. There are so many contenders here. But if she gets into the final, and the pace will be slow - she has an extremely good finish. Good enough for a medal? We will see.
It's also hard not to like Maria Andrejczyk in women's javelin - she was 4th in Rio, great in qualifications (if i'm not mistaken here, her throw in the qualis would give her a gold in the final, but I need to check it). Unfortunately she also had problems with health, so it is hard to say if she can repeat her Rio performance at least.
There are some youngsters shining already - Klaudia Siciarz in 100 hurdles for example, but it is a chance for a medal in Paris, I would say. I will look out how her career will unfold. She has a talent and potential for sure.
And finally, I would be supersuperhappy if we get a medal in men's high jump. This is by far my favourite event. As somebody told here before speaking about fencing - this is because of my good personal memories. But we don't have a good male high jumper in Poland now. Good enough to have a real chance for a medal.
In women's high jump there is Kamila Lićwinko. I wish her all the best but it will be very difficult for her to get on the podium. And from my personal point of view I wouldn't wish her e.g. a bronze medal after two Ukrainian jumpers which would be achieved only because Maria Lasitskene wasn't there. If you want to get a well-deserved olympic medal, win it in a strongest possible field ever. Otherwise, it will not taste the same. And I understand what Russians did was outrageous (maybe there should be a better word for that but my English is not so good). But I don't think that people like Lasitskene or Sidorova - who didn't fault with doping rules personally, should not be able to compete in the olympics. If it would happen under Russian flag or not - well, maybe without this flag but - as Barrack Obama said - this question is above my pay grade.
Anyway, I am a kind of multi-kulti person and I must admit that I watch olympics primarily to enjoy good, tense competitions - whether Poles are getting 3 gold medals in one day or not.
All the best for you, enjoy your weekend.