The word appears 2 times.
This book is constantly talking about the character of the Negro. Not always unflatteringly, but not with much warmth either. I'd have to conclude that Ian Fleming was something of a racist. All the black dialog is as bad as you would find in Mark Twain. The only black character with any education is Mr. Big - the villain.
..... In all fairness, this line in this book refers to the slang term for the segregated balcony seating for blacks in theaters.
'One can try,' said Leiter. 'But I know what you mean - better the frying-pan you know than the fire you don't. It isn't a bad life when it consists of sitting in a comfortable bar drinking good whiskey. How do you like this corner of the jungle?' He leaned forward. 'Just listen to the couple behind you. From what I've hear they're straight out of "Nigger Heaven".'
.....But later in the book... When Bond has rescued Solitaire from Mr. Big, her comment is..
"She smiled. 'I thought I'd get my chance one day.' She gestured toward the windows. 'You've given me a new life. I've been shut up with him and his nigger gangsters for nearly a year. This is heaven."