user70578: If I am trying to find a nonce and in the meantime someone finds a nonce and adds a new block to chain, then will my work be wasted or it could be useful in finding other nonces?

user49354: your work is "wasted" caused by the mining-algorithm.
you have found a new block if sha2(sha2(blockheaderOfnewBlock) starts with a certain amount of zeros. the blockheader contains a nonce, the hash of the previous block and some other information. since the previous-block-hash is another hash if a new block was found you have another information-base for your mining-software. 

user48884: It is "wasted". All block hashes calculated in the mining process are completely independent of each other. It is effectively random guessing; there is no progress that is being made and finding a hash does not make it more likely that the next one is a valid block hash. They are independent trials and each one is useless for calculating the next hash. So any hash that is not a valid block hash is "wasted".

70578: <p>If I am trying to find a nonce and in the meantime someone finds a nonce and adds a new block to chain, then will my work be wasted or it could be useful in finding other nonces?</p>
 49354: <p>your work is "wasted" caused by the mining-algorithm.</p>

<p>you have found a new block if <code>sha2(sha2(blockheaderOfnewBlock)</code> starts with a certain amount of zeros. the blockheader contains a nonce, the hash of the previous block and some other information. since the previous-block-hash is another hash if a new block was found you have another information-base for your mining-software. </p>
 48884: <p>It is "wasted". All block hashes calculated in the mining process are completely independent of each other. It is effectively random guessing; there is no progress that is being made and finding a hash does not make it more likely that the next one is a valid block hash. They are independent trials and each one is useless for calculating the next hash. So any hash that is not a valid block hash is "wasted".</p>
