Is it worth selling my nikon d90 and buy compact camera?

And suggest some good compact camera at least equivalent to nikon d90 or superior to it.

Added (1). because i'm too lazy to carry d90 around… Should i just buy new compact camera or sell it? I'm confuse

No, and there are none. The few compacts that can even come close to the D90 cost as much as a new DSLR anyway.

A DSLR is superior to any compact. The only thing the compacts have as an advantage is size. Hard to put a D90 in your pocket.

As for recommendations, set a budget of how much you are willing to spend on this compact, and look at that price point. Sort them by whatever criteria are important to you, and buy the one on top of the list. They are all pretty much the same at each price level. The only major difference is amount of zoom.

There's no compact camera equivalent or superior to a DSLR like your D90. It will have a larger sensor & be capable of a lot more than than any compact.

Do not be put off by the megapixel count of the D90 or that it's 'old' technology. In terms of image quality it will blow a compact camera out of the water.

No compact camera is equivalent, much less superior to a Nikon D90.

Nope

No.

There's no harm in buying a compact as a back-up camera, and always keeping it in your jacket pocket, but there's no substitute for a DSLR - especially a classic like the D90.

If laziness is enough to disregard a fine piece of equipment like the D90 then so be it. Lucky is the person who'll grab it. There's no compact, past, present or future, that will effectively replace it.

If you can afford it, you should probably hold onto the D90 for situations in which you can tolerate the weight and bulk.
You can't take pictures with a camera that is not with you, so it is worthwhile to get something more compact. There's quite a range of choices. The compacts with little 1/2.3" sensors make it easy to design lenses with a lot of zoom range and low cost and weight for the range. However, you do take a big hit in image quality from noise and noise reduction artifact. There are premium compacts with a little bigger and better sensors, and some compact system cameras with less weight and a little better quality, although the compactness becomes not so terrifically compact as you add lenses to extend its range of focal lengths.

You won't get much for your D90, however it's futile people encouraging someone to continue usinng a DSLR if they have decided it is just too bulky or awkward to use.

You need a Sony RX100 mk3 to get similar image quality. See these Flikr links.
Some images from the D90…

and images from the Sony

If you want a superzoom then get a Fuji HS50 EXR, but it will be almost as heavy as a DSLR.
Images from that camera…