I keep seeing people say that fats like avocado, nuts, etc., are “healthy”, but I personally do not agree.
What are the possible issues with high amounts of PUFAs? One is that certain PUFAs might cause fat cells to be insulin sensitive, meaning your fat cells allow insulin and blood sugar into them. You’re getting fatter. (By contrast, saturated fat might cause your fat cells to be insulin resistant, meaning they don’t allow insulin and blood sugar into them; you’re getting skinnier.)
See this:
The second is that high amounts of PUFAs might CAUSE whole-body insulin resistance:
From the discussed study, which is a mouse study:

The highest graph is a graph of 22.5% linoleic acid, a PUFA (from sunflower and safflower oils, I believe). At some point, high levels of PUFAs might cause whole-body insulin resistance. (Yes, this is a study on mice, which I know might not be directly transferable to humans, but is illustrative for what might happen.)
So, if you are eating a lot of nuts, chicken, avocados and find yourself not losing weight, it might not be the fat content or calories per se, but the TYPE of fat you are eating that is causing you issues.
See also the following:
https://proteinpower.com/drmike/2016/07/27/are-nuts-paleo/
No one knows what the amount of PUFAs are we can have and not have deleterious effects. But if you find yourself at an impasse in weight loss and do not know why, look at what you’re eating and see what your daily PUFA intake is.