While its similarity to 好久不見 (hao jiu bu jian)is notable, I haven't seen any proof that this is actually a "loan translation," and I'm not sure you could ever "prove" such a thing.
1900W. F. DRANNAN 31 Yrs. on Plains (1901) xxxvii. 515 When we rode up to him [sc. an American Indian] he said: ‘Good mornin. Long time no see you.’ 1939R. CHANDLER in Sat. Even. Post 14 Oct. 72/4 Hi, Tony. Long time no see. 1940[see HIYAint.]. 1959D. BEATY Cone of Silence viii. 105 ‘Hello, Clive.’ ‘Long time no see.’ 1959C. MACINNES Absolute Beginners 68 Hail, squire... Long time no see. 1971D. E. WESTLAKE I gave at the Office (1972) 164 ‘Hello, Arnold,’ I said... ‘Long time no see.’