How could something possibly be for all nations while the other is for Israel and the world. It's really that the Law of Moses was for Israel but contains some pre-existing and on-going universal application apart from ceremonies and dietary items.
Here is what the scripture reveals "God spoke to Noah" after the flood.
Genesis 8:15-22 NASB - 15 Then God spoke to Noah, saying, 16 "Go out of the ark, you and your wife and your sons and your sons' wives with you. 17 "Bring out with you every living thing of all flesh that is with you, birds and animals and every creeping thing that creeps on the earth, that they may breed abundantly on the earth, and be fruitful and multiply on the earth." 18 So Noah went out, and his sons and his wife and his sons' wives with him. 19 Every beast, every creeping thing, and every bird, everything that moves on the earth, went out by their families from the ark. 20 Then Noah built an altar to the LORD, and took of every clean animal and of every clean bird and offered burnt offerings on the altar. 21 The LORD smelled the soothing aroma; and the LORD said to Himself, "I will never again curse the ground on account of man, for the intent of man's heart is evil from his youth; and I will never again destroy every living thing, as I have done. 22 "While the earth remains, Seedtime and harvest, And cold and heat, And summer and winter, And day and night Shall not cease."
Here "God blessed Noah and his sons and said this to them".
Genesis 9:1-19 NASB - 1 And God blessed Noah and his sons and said to them, "Be fruitful and multiply, and fill the earth. 2 "The fear of you and the terror of you will be on every beast of the earth and on every bird of the sky; with everything that creeps on the ground, and all the fish of the sea, into your hand they are given. 3 "Every moving thing that is alive shall be food for you; I give all to you, as I gave the green plant. 4 "Only you shall not eat flesh with its life, that is, its blood. 5 "Surely I will require your lifeblood; from every beast I will require it. And from every man, from every man's brother I will require the life of man. 6 "Whoever sheds man's blood, By man his blood shall be shed, For in the image of God He made man. 7 "As for you, be fruitful and multiply; Populate the earth abundantly and multiply in it." 8 Then God spoke to Noah and to his sons with him, saying, 9 "Now behold, I Myself do establish My covenant with you, and with your descendants after you; 10 and with every living creature that is with you, the birds, the cattle, and every beast of the earth with you; of all that comes out of the ark, even every beast of the earth. 11 "I establish My covenant with you; and all flesh shall never again be cut off by the water of the flood, neither shall there again be a flood to destroy the earth." 12 God said, "This is the sign of the covenant which I am making between Me and you and every living creature that is with you, for all successive generations; 13 I set My bow in the cloud, and it shall be for a sign of a covenant between Me and the earth. 14 "It shall come about, when I bring a cloud over the earth, that the bow will be seen in the cloud, 15 and I will remember My covenant, which is between Me and you and every living creature of all flesh; and never again shall the water become a flood to destroy all flesh. 16 "When the bow is in the cloud, then I will look upon it, to remember the everlasting covenant between God and every living creature of all flesh that is on the earth." 17 And God said to Noah, "This is the sign of the covenant which I have established between Me and all flesh that is on the earth." 18 Now the sons of Noah who came out of the ark were Shem and Ham and Japheth; and Ham was the father of Canaan. 19 These three were the sons of Noah, and from these the whole earth was populated.