In the 1990s, she wrote lyrics and recorded ballads, resulting in several platinum singles and her biggest sales: "Tōi Machi no Doko ka de..." (1991), "Sekaijū no Dare Yori Kitto" (1992) with Wands, and "Tada Nakitaku Naru no" (1994).

[4] By the 1990s, her artistry began to mature as she penned lyrics and recorded ballads, resulting in several platinum singles and her biggest sales: "Tōi Machi no Doko ka de..." (1991), "Sekaijū no Dare Yori Kitto" (1992) with Wands, and "Tada Nakitaku Naru no" (1994).

[5][3] In 1995, director Shunji Iwai cast Nakayama in the starring dual roles of Hiroko Watanabe and Itsuki Fujii in the film Love Letter.

[8][3] On 8 November 2021, Nakayama starred alongside King & Prince member Yuta Jinguji in the stage play Aoi no Ue/Yoroboshi (『葵上』『弱法師』, Lady Aoi/Weak Lawyer) at The Globe Tokyo.

[9][10] From 1985, she was represented by Big Apple Co., Ltd.[11][12] Nakayama was nominated for a Best Actress Japanese Academy Award in 1998 for her role in Tokyo Biyori,[13] and has appeared in numerous TV series including Love Story (2001).

[2] Two years after her friend Yasuko Endō died by suicide, Nakayama wrote the lyrics and composed the music for the song, "Long Distance to Heaven," that she performed during a 1988 concert tour.

[20][21] Police later announced that they found no signs of foul play after conducting an autopsy, while agency Big Apple said in a statement that Nakayama died due to an accident while she was bathing.