From the King James translation; There are several Scriptures which tell us that God is Omnipotent, Not the least of which is creation itself.
Then the first time God brought rain upon the Earth He caused a flood which Killed all life except Those animals he saved and those eight people aboard the Ark.
Beyond that we see God parting the red sea, for Israel, and drowning Pharaoh's Army in it.
God stopped the Rain for three years, at the behest of Elijah.
He also caused wood soaked with massive amounts of water to burn when he sent fire from Heaven.
He took Elijah to Heaven in a whirlwind as Elisha watched.
He caused Elisha's mule to talk.
He caused the sun to retreat 10 hours.
And that is a few of the passages covered in only in the Old Testament.
So let's look at Jesus in the New Testament.
Matthew 9:6 But that ye may know that the Son of man hath power on earth to forgive sins, (then saith he to the sick of the palsy,) Arise, take up thy bed, and go unto thine house.
Jesus not only claimed to have the power of God but he also demonstrated it, in that passage.
Matthew 28:18 And Jesus came and spake unto them, saying, All power is given unto me in heaven and in earth.
In the above passage Jesus is telling us His power is given to him by the Father.
Mark 14:62 And Jesus said, I am: and ye shall see the Son of man sitting on the right hand of power, and coming in the clouds of heaven.
Here Jesus is telling us that one day we will see him sitting next to the Father who is Power.
Luke 1:35 And the angel answered and said unto her, The Holy Ghost shall come upon thee, and the power of the Highest shall overshadow thee: therefore also that holy thing which shall be born of thee shall be called the Son of God.
Here we find the Angel Gabriel telling Mary that It is God's power that will cause her to become pregnant yet remain a virgin.
I could go on citing Scriptures from both the Old and New Testaments attesting to God's omnipotence, but either you believe that the Bible is true or you do not, but in answer as to whether there is Biblical backup for God's omnipotence the answer is a resounding yes!