The Tigers boss is keen on the Arsenal striker after getting him on loan to both Birmingham City and Sunderland in the past but admits his enormous wages may make it difficult to bring the Denmark international to the KC Stadium.
"Everyone assumes that but the problem with Nick is whether I can afford him. He has a huge salary," said Bruce.
"I've been able to get him on loan at my last two clubs. I know the lad, he has terrific ability, but it's difficult with the amount of money he earns at the minute.
"For us to go and make a huge difference, to get a striker who can get 20 goals a year, where does a club like ours get them?
"They are few and far between and, if they are capable of getting 20 goals a season, they're usually too expensive.
"Can you get one in? It's always difficult but we're always trying. We're looking to get maybe one more in. That will prove difficult but we're working away."