If posting a giant, heart shaped ring on your ring finger on Instagram in response to engagement rumours by fans means engaged, then yes she is.
If not, then I guess not.
Looking at things, however; all indications point to Nicki Minaj on the way to putting her spinsterhood behind her. The Anaconda rapper last night posted a pic of her hand, sporting some serious bling on her ring finger, with some very suggestive emojis.
This is after an earlier pic of her and new boo Meek Mill had gotten fans talking, after they noticed she had a ring on her ring finger.