Actually, not quite - this is her first live in three years, to quote her FB. (https://www.facebook.com/eri.nobuchika.1)
She's also on Twitter, though there are zero posts on her Twitter account. She just created her Facebook account at the end of November last year, though, so this might be a sign that she'll gradually resume her activities as a singer.
The event had Osawa Shinichi participating, which may have been why she got called to attend. Who knows, she might end up releasing something with Osawa or Kobayashi Takeshi at the helm, since the venue she sang at, Yoyogi Village, was produced by the both of them. (http://www.yoyogi-village.jp/top/index.php).