A new manager is expected to be announced next week with Eddie Howe the man likely to replace Neil Lennon.
Following a disastrous season where the club lost its stranglehold of domestic football, there will be a new look Celtic team next season.
Nisbet, reported to be worth £3million, has had an impressive breakthrough top-flight season following his six-figure transfer from Dunfermline Athletic last summer.
The 24-year-old, who has also been linked with Brentford, has struck 18 goals in all competitions leading to his Scotland debut in March.
He dropped out the starting XI for a spell at the end of January after Birmingham City put in a bid leading to a transfer request to be submitted from the player.
The former Partick Thistle youngster could lead the club to Scottish Cup glory next week.
Meanwhile, Bologna ace Hickey has impressed during his maiden Serie A season before injury ended his campaign. The 18-year-old played 11 times in the Italian top-flight. He suffered a shoulder injury earlier this year which required surgery.
Capable of playing at left-back, right-back, part of a back three or as a wing-back, the former Hearts star left Tynecastle last summer in a deal worth around £1.8million when there was interest from Celtic.
Hickey had been at Celtic when he was younger before making the switch to Gorgie. He would be expected to cost upwards of £4million.