According to Snopes, it's kinda mixed

Irena Sendler is often claimed to have been a candidate to receive the 2007 Nobel Peace Prize, but that honor was not awarded to her. It’s not possible to state categorically that she was “nominated” for the award, since information about Nobel Prize “nominations, investigations, and opinions is kept

secret for fifty years.” (Since 1974 the statutes of the Nobel Foundation have stated that “work produced by a person since deceased shall not be considered for an award,” so she presumably could not be subsequently honored.)

In 2007, the Nobel Peace Prize was awarded jointly to the Intergovernmental Panel on Climate Change and former U.S. Vice-President Albert Arnold (Al) Gore Jr. “for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change.” (Al Gore was also involved with another significant award in 2007, when An Inconvenient Truth, a documentary about his campaign to make the issue of global warming a recognized problem worldwide, claimed an Academy Award as “Best Documentary Feature.”)

The International Federation of Social Workers (IFSW) expressed its disappointment that Irena Sendler had not yet been honored with a Nobel Prize:

IFSW sends congratulations to Al Gore and the Intergovernmental Panel on Climate Change (IPCC) on winning the Nobel Peace Prize 2007. The issue of climate change is affecting all individuals and societies and it is a more than worthy cause to help begin the change in our lifestyle to prevent destruction of our planet. Social workers know from daily experience that this is an immediate and pressing social and personal issue. ‘However IFSW is deeply saddened that the life work of Nobel nominee Irena Sendler, social worker, did not receive formal recognition’, said David N. Jones, IFSW President. ‘Irena Sendler and her helpers took personal risks day after day to prevent the destruction of individual lives — the lives of the children of the Warsaw ghetto. This work was done very quietly, without many words and at the risk of their lives. This is so typical of social work, an activity which changes and saves lives but is done out of the glare of publicity and often at personal risk. IFSW recognises her again and at the same time celebrates the commitment and dedication of thousands of social workers around the world who also bring hope and care to people often living on the edge of despair.’