I was running a batch and by mistake, I set LIMIT in the query as 1 instead of 1000 now it is flooding with debug logs and I not responding. I have deleted all pending scheduled jobs. SO my question is how should I kill running chain and how should I recover dev console?
To free up the Developer Console you could stop the flood of Log entries coming in. It is likely responding to the Streaming API event every time a new log is published and running a query to find all the latest logs.
To stop the logs coming in you can delete or alter the TraceFlag for the current user. One option would be to do this via Setup - See Customize Trace Flags and Debug Levels in Setup. You could also do this via the APIs directly, but the Setup UI would be the simplest.
Once the flood of logs is stopped you can then look at killing the run away job.