Which one of the following statements is not correct?

Option B is incorrect because Tuluva Narasa Nayaka was not the founder of the Tuluva dynasty. The Tuluva dynasty was actually founded by Tuluva Narasa Nayaka's elder brother, Tuluva Vira Narasimha Raya.

Option A: Krishnadeva Raya did indeed write Amuktamalyada, which is a famous Telugu composition.

Option C: The Tuluva dynasty court was indeed adorned by the Ashtadiggajas, which translates to "eight great poets" who were patrons of literature and culture during the Vijayanagara Empire.

Option D: Tuluva Narasa Nayaka did maintain friendly relations with the Portuguese, which was a significant aspect of the Vijayanagara Empire's diplomatic relations during his reign.

Therefore, the correct answer is Tuluva Narasa Nayaka was the founder of the Tuluva dynasty, which is not correct.