“There's nothing good on right now.”
You're changing the channels on the TV and looking for something to watch, but nothing looks interesting. You say this to yourself.
There's nothing good on right now.
This phrase means "nothing is (there)". It's used to describe a situation that is uninteresting and uneventful.
This phrase can be used with the word "there":
I answered the door when I heard the knock, but there was no one there.
Or it can be used with a phrase that indicates where you're talking about:
There's no one at work except me.
You can use the word "happening" to say that there are no interesting situations or events:
There's not much happening right now, so I think I'll take a break.
Using "there is" is good when you're describing a general situation, rather than a specific person or thing. If you want to be more specific about the person or thing, use "___ is ___":
No one is at work except me.
This is a verb used to discuss TV shows. A TV show is "on" if it is playing right now:
Hey Jake, I think "Dancing with the Stars" is on.
You can talk about the quality of the TV shows that are on this way:
Is there anything interesting on?
There's nothing good on.
The word "now" can mean a few different things. It can mean the present moment:
I'm cooking dinner now.
Or it can mean a longer period of time:
I live in Utah now.
The phrase "right now" sounds a little shorter than "now".