Chelsea goalkeeper Nathan Baxter has also joined on loan.
"The manager (John Coleman) said he's been an admirer of mine for many years and that he'd tried to sign me in the past," said Nottingham, 31, who has signed a three-year contract.
"He feels like I can play a massive part in taking the club forward.
Baxter, 21, has had previous loan spells at Yeovil and Ross County.
"It's a club that ticks all the boxes for me and I'm delighted to be here," he told the League One club's website.
Baxter becomes the third Chelsea player to join Accrington this summer, with Tariq Uwakwe and Jon Russell also signing season-long loan deals.
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