I want to use mischief as a noun. Above sentence sounds a little awkward as I have never seen anyone using it this way. Is there a more suitable replacement?
Mischief is always a noun, but it is a non-count noun: it designates a kind or quality of behavior, not an individual instance of such behavior. Thus you may say
ok I am tired of your mischief. BUT NOT
∗ I am tired of your mischiefs.
What word you use to designate individual instances will depend on exactly how you want to characterize the behavior. Mischief is used colloquially mostly of behavior springing from exuberance and humour rather than real malice; if that is what you mean, tricks or pranks might work.
I warn you, Sandeep: your tricks have not gone unnoticed.
In formal contexts, mischief has a graver sense, denoting in law malicious and wanton actions which cause damage or injury, and in other contexts the damaging consequences of action rather than the action itself:
As serious as these problems were, they masked the real mischief created by Democratic state banking policies.
In the sense of consequences, plural mischiefs is not uncommon; but it is probably not what you have in mind.
You're correct that the word mischief isn't really correct or comfortable used in that way.
You might use mischief in - 'I wonder what mischief the dog will get up to whilst I pop to the shops'.
The word mischief usually implies minor transgressions, naughty rather than malicious.
I would replace the word with shenanigans. The form and sound of the word reinforces the lighter meaning of mischief.